Kepler-23 b
Kepler-23 b is a super-Earth orbiting Kepler-23 in the constellation Cygnus. It lies about 2,726 light-years from Earth and was discovered in 2011 using the transit method.
How Big Is Kepler-23 b?
Kepler-23 b has a radius of 1.64 times that of Earth. Its mass is 2.6 times that of Earth, giving it a density of 3.19 g/cm³ — between that of rocky and gaseous planets.
Is Kepler-23 b in the Habitable Zone?
The position of Kepler-23 b relative to the habitable zone of Kepler-23 cannot be precisely determined from the available orbital data.
Habitable zone of Kepler-23: 1.178–2.773 AU (conservative: 1.493–2.629 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on Kepler-23 b — one full orbit around Kepler-23 — lasts 7.10 Earth days, shorter than Mercury's 88-day year. Its orbit is nearly circular (eccentricity 0.017).
How Was Kepler-23 b Discovered?
Kepler-23 b was discovered in 2011 using the transit method, with observations from Kepler.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is Kepler-23 b?
Kepler-23 b is 2,725.9 light-years (835.8 parsecs) from Earth. Light arriving here tonight left the planet about 2,726 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 47,975,840 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. Kepler-23 b scores 0.26, ranking #2,794 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-23
Kepler-23
- Surface temperature
- 5,828 K (Sun: 5,772 K)
- Mass
- 1.08 M☉
- Radius
- 1.55 R☉
The Kepler-23 Planetary System
Kepler-23 b is one of 3 known planets in the Kepler-23 system. Its siblings:
- Kepler-23 c (Sub Neptune)
- Kepler-23 d (Mini Neptune)
Kepler-23 b — Complete Data
| Radius | 1.638 Earth radii (0.146 Jupiter radii) |
|---|---|
| Mass | 2.56 Earth masses (0.008 Jupiter masses) |
| Density | 3.19 g/cm³ (Earth: 5.51) |
| Orbital period | 7.10 days |
| Eccentricity | 0.017 |
| Earth Similarity Index | 0.26 |
| Distance from Earth | 2,725.9 light-years (835.8 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2011 |
Data: NASA Exoplanet Archive, last updated 2024-06-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-23 b
Is Kepler-23 b habitable?
Kepler-23 b is not known to orbit within the habitable zone of Kepler-23, and as a super-Earth it is an unlikely candidate for life as we know it.
How far away is Kepler-23 b?
Kepler-23 b is about 2,726 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 47,975,840 years to get there.
How big is Kepler-23 b compared to Earth?
Kepler-23 b has 1.64 times the radius of Earth and about 2.6 times its mass.
How long is a year on Kepler-23 b?
One orbit around Kepler-23 takes 7.1 Earth days — short enough that 51 of its years would fit into one Earth year.
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